Pi Mensae is a white to yellow subgiant star that can be located in the constellation of Mensa. It is calculated at being 4.000 Billion Years old. This information comes from ExoPlanet. Pi Mensae is the Bayer Classification for the star. HIP26394 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD39091.
The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For Pi Mensae, the location is 05h 37m 08.79 and -80d28`18.0 .
All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving 1,050.38 ± 000.20 towards the north and 312.01 ± 000.21 east if we saw them in the horizon.
Pi Mensae has a spectral type of G3IV. This means the star is a white to yellow subgiant star. The star has a B-V Colour Index of 0.6 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,895 Kelvin.
Pi Mensae has been calculated as 1.21 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 840,189.99.km. The star's solar mass is 1.00 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.
The star's metallicity is 0.090000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.
The star is believed to be about 4.00 Billion years old. To put in context, the Sun is believed to be about five billion years old and the Universe is about 13.8 billion years old.
Pi Mensae has an apparent magnitude of 5.65 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of 4.35 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.34. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.
Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 54.92 which gave the calculated distance to Pi Mensae as 59.39 light years away from Earth or 18.21 parsecs. It would take a spaceship travelling at the speed of light, 59.39 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.
In 2007, Hipparcos data was revised with a new parallax of 54.60 which put Pi Mensae at a distance of 59.74 light years or 18.32 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.
|Bayer Designation||Pi Mensae|
|Hipparcos Library I.D.||26394|
|Henry Draper Designation||39091|
|Star Type||subgiant star|
|Age||4.000 Billions of Years|
|Absolute Magnitude||4.35 / 4.34|
|Right Ascension (R.A.)||05h 37m 08.79|
|1997 Distance from Earth||54.92 Parallax (milliarcseconds)|
|59.39 Light Years|
|2007 Revised Distance from Earth||54.60 Parallax (milliarcseconds)|
|59.74 Light Years|
|Proper Motion Dec.||1050.38 ± 0.20 milliarcseconds/year|
|Proper Motion RA.||312.01 ± 0.21 milliarcseconds/year|
|Colour||(G) White to Yellow|
|Radius (x the Sun)||1.21|
|Calculated Effective Temperature||5,895 Kelvin|
|Mass Compared to the Sun||1.00|